Blue sulfur dye and process of making same.



UNITED STATES Patented June 30, 1903.

PATENT OFFICE.

ASSIGNORS TO LEVINSTEIN, LIMITED, OF MANCHESTER,

ENGLAND.

BLUE SULFUR DYE AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 732,090, dated June 30, 1903. Application filed June 10, 1902. Serial No. 111,022. (No specimens.)

To all whom it may concern.-

Be it known that we, IVAN LEVINSTEIN and HERBERT LEVINsTEIN, Ph. D. subjects of the King of Great Britain and Ireland, residing at Manchester, in the county of Lancaster, England, have invented new and useful Improvements in Blue SulfurDyestufiandProcesses of Making Same, of which the following is a specification.

It is well known that certain mono-alkylleuco-indophenols when treated with sodium sulfid and sulfur under suitable conditions yield blue dyestuifs which dye unmordanted cotton bright blue shades, which are not very fast either to light or to washing.

We have discovered a process for preparing chlorinated mono alkyl leuco indophenols and that these when treated under suitable conditions with sodium sulfid and sulfur-yield dyestuffs which are in general similar to the corresponding unchlorinated dyestuffs, but are greatly superior to them both in fastness to light and to washing.

Our mode of preparation is illustrated by the following examples:

Example I. Preparation of para ethylamz'dometaioZg Z paraowymeta chlorophenylamin.-6.75 kilos of ethyl-orthotoluidin are added, with stirring, to a solution of 7.2 kilos 'of ortho chloropara amidophenol (meltingpoint 153 centigrade) in 12.5 kilos of concentrated sulfuric acid (66 Baum) and two hundred liters of water. A solution of 12.5 kilos of potassium bichromate in one hundred and fifty liters of water is now added in the cold and with good stirring in order to form an indophenol. The latter substance is then precipitated with soda, filtered off, and washed. It is then stirred into a paste with one hundred and thirty liters of water and reduced with a cold solution of twenty-five kilos of sodium sulfid and one hundred and twenty five liters of water. When the reduction is complete, the solution is heated to 70 centigrade and filtered. From the filtrate paraethyl amidometatolyl paraoxymeta chlorophenylamin is precipitated by means of sodium bicarbonate and may be directly employed for the production of a blue dyestulf.

Analogous chlorinated derivatives of leuco indophenol maybe similarly prepared by substituting in the above example equivalent amounts of orthotoluidin or paraxylidin for the ethyl-orthotoluidiu. A very similar result is obtained if for ethyl-orthotoluidin an equivalent amount of methylor other alkylorthotoluidin be taken.

Example II. -len kilos of para-ethyl-amidometatolyl-paraoxyineta-chlorophenylamin, prepared as described under Example I, are added to a solution containing twenty kilos of sulfur, fifty kilos of crystallized sodium sulfid, and thirty liters of water. The rnixture is concentrated by boiling down until the boiling-point is 115 centigrade and is then heated to that temperature for about twenty-four hours in a pan provided with a reflux condenser. After the reaction is over the dyestuff is precipitated most advantageously by blowing in a current of air and is filtered off, dried, and finely ground. It is thus obtained in the form of a blue powder readily soluble in concentrated sulfuric acid with blue color and in caustic-soda solution with red-violet color, but is practically insoluble in water or alcohol. The solution in sodium sulfid is colorless.

The dyestuif dyes unmordanted cotton from a bath containing sodium sulfid very brightindigo-blue shades, which are veryfast to washing and to light.

What we claim as our invention, and desire to secure by Letters Patent, is-- l. The process of producing blue sulfur dyestuffs which consists in oxidizing together orthochloropara-amidophenol and mono-alkylorthotoluidin to form an indophenol, reducing the same and thereby producing paramono alkyl amidometatolylparaoxymetachloroparaoxyphenylamin having the probable constitution (alkyl) Nn-o,n, on, -NH o,H, oH c1, and which is a white powder sparingly soluble in alcohol and in Water, very sparingly soluble in benzene, and which turns blue on exposure to the atmosphere, and heating the intermediate product thus obtained with sulfur and an alkali snlfid, substantially as set forth.

2. The new blue sulfur dyestuft prepared from paramonoalkylamidometatolyl-paraoxymetachlorophenylamin, which dyestuflf in the dry state is a blue substance soluble in concentrated sulfuric acid with blue color, in caustic soda With a red-violet color, and which dyes unmordanted cotton in bright indigoblue shades of great fastness both to light names to this specification in the presence of two subscribing witnesses.

IVAN LEVINSTEIN. HERBERT LEVINSTEIN. Witnesses tothe signature of Ivan Levinstein:

WM. F. COOPER, WILLIAM E. HEYS. Witnesses to the signature of Herbert Levinstein:

and to washing, substantially as set forth. WILLIAM E. HEYs,

In testimony whereof We have signed our l ARTHUR MILLWARD. 

